Method using epitaxial transfer to integrate HAMR photonic integrated circuit (PIC) into recording head wafer

ABSTRACT

Embodiments of the present invention generally relate to a method for forming a HAMR device having a photonic integrated circuit that includes an optical detector, an optical emitter, and an optical element distinct from the optical detector and the optical emitter, where the elements of the photonic integrated circuit are aligned with a near field transducer. The method includes forming one or more layers on a substrate, bonding the layers to a partially fabricated recording head, removing the substrate using epitaxial lift-off, and forming the optical elements on the partially fabricated recording head.

BACKGROUND

1. Field

Embodiments of the present invention generally relate to data storagesystems, and more particularly, to thermally assisted recording devices.

2. Description of the Related Art

Higher storage bit densities in magnetic media used in disk drives havereduced the size (volume) of magnetic bits to the point where themagnetic bit dimensions are limited by the grain size of the magneticmaterial. Although grain size can be reduced further, the data storedwithin the magnetic bits may not be thermally stable. That is, randomthermal fluctuations at ambient temperatures may be sufficient to erasedata. This state is described as the superparamagnetic limit, whichdetermines the maximum theoretical storage density for a given magneticmedia. This limit may be raised by increasing the coercivity of themagnetic media or by lowering the temperature. Lowering the temperaturemay not always be practical when designing hard disk drives forcommercial and consumer use. Raising the coercivity, on the other hand,requires write heads that incorporate higher magnetic moment materials,or techniques such as perpendicular recording (or both).

One additional solution has been proposed, which uses heat to lower theeffective coercivity of a localized region on the magnetic media surfaceand writes data within this heated region. The data state becomes“fixed” once the media cools to ambient temperatures. This technique isbroadly referred to as “thermally assisted (magnetic) recording” (TAR orTAMR), “energy assisted magnetic recording” (EAMR), or “heat-assistedmagnetic recording” (HAMR) which are used interchangeably herein. It canbe applied to longitudinal and perpendicular recording systems as wellas “bit patterned media”. Heating of the media surface has beenaccomplished by a number of techniques such as focused laser beams ornear-field optical sources.

Typically, external optoelectronic devices such as lasers or photodiodesare integrated into a finished slider through optical coupling tovarious waveguides that then guide and focus the light onto a plasmonicnear field transducer used to generate the heat spot. This approachrequires challenging mechanical alignment operations in order to achievethe necessary efficient coupling to the waveguide.

Therefore, an improved method for forming a HAMR device is needed.

SUMMARY OF THE INVENTION

Embodiments of the present invention generally relate to a method forforming a HAMR device having a photonic integrated circuit that includesan optical detector, an optical emitter, and an optical element distinctfrom the optical detector and the optical emitter, where the elements ofthe photonic integrated circuit are aligned with a near fieldtransducer. The method includes forming one or more layers on asubstrate, bonding the layers to a partially fabricated recording head,removing the substrate using epitaxial lift-off, and forming the opticalelements on the partially fabricated recording head.

In one embodiment, a method for forming a heat assisted magneticrecording device is disclosed. The method includes forming a partiallyfabricated recording head on a first substrate, forming a sacrificiallayer on a second substrate, forming one or more additional layers onthe sacrificial layer, bonding the one or more additional layers to thepartially fabricated recording head opposite the first substrate,performing epitaxial lift-off to remove the sacrificial layer and thesecond substrate, and patterning the one or more additional layers toform a plurality of optical elements.

In another embodiment, a method for forming a heat assisted magneticrecording device is disclosed. The method includes forming a partiallyfabricated recording head on a first substrate, forming a sacrificiallayer on a second substrate, forming one or more additional layers onthe sacrificial layer, forming a third substrate over the one or moreadditional layers, performing epitaxial lift-off to remove thesacrificial layer and the second substrate, bonding the one or moreadditional layers to the partially fabricated recording head oppositethe first substrate, removing the third substrate, and patterning theone or more additional layers to form a plurality of optical elements.

In another embodiment, a heat assisted magnetic recording device isdisclosed. The heat assisted magnetic recording device includes anoptical detector, an optical emitter, an optical element distinct fromthe optical detector and the optical emitter, and a near fieldtransducer, wherein the optical detector, the optical emitter, and theoptical element are aligned with the near field transducer.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIGS. 1A-1B illustrate a disk drive system, according to embodiments ofthe invention.

FIG. 2 illustrates a cross-sectional schematic diagram of a HAMR enabledhead of a disk drive, according to one embodiment of the invention.

FIGS. 3A-3F illustrates a process of making a HAMR enabled head,according to one embodiment of the invention.

FIGS. 4A-4G illustrates a process of making a HAMR enabled head,according to one embodiment of the invention.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

In the following, reference is made to embodiments of the invention.However, it should be understood that the invention is not limited tospecific described embodiments. Instead, any combination of thefollowing features and elements, whether related to differentembodiments or not, is contemplated to implement and practice theinvention. Furthermore, although embodiments of the invention mayachieve advantages over other possible solutions and/or over the priorart, whether or not a particular advantage is achieved by a givenembodiment is not limiting of the invention. Thus, the followingaspects, features, embodiments and advantages are merely illustrativeand are not considered elements or limitations of the appended claimsexcept where explicitly recited in a claim(s). Likewise, reference to“the invention” shall not be construed as a generalization of anyinventive subject matter disclosed herein and shall not be considered tobe an element or limitation of the appended claims except whereexplicitly recited in a claim(s).

Embodiments of the present invention generally relate to a method forforming a HAMR device having a photonic integrated circuit that includesan optical detector, an optical emitter, and an optical element distinctfrom the optical detector and the optical emitter, where the elements ofthe photonic integrated circuit are aligned with a near fieldtransducer. The method includes forming one or more layers on asubstrate, bonding the layers to a partially fabricated recording head,removing the substrate using epitaxial lift-off, and forming the opticalelements on the partially fabricated recording head.

FIG. 1A illustrates a disk drive 100 embodying this invention. As shown,at least one rotatable magnetic disk 112 is supported on a spindle 114and rotated by a disk drive motor 118. The magnetic recording on eachdisk is in the form of annular patterns of concentric data tracks (notshown) on the magnetic disk 112.

At least one slider 113 is positioned near the magnetic disk 112, eachslider 113 supporting one or more magnetic head assemblies 121 that mayinclude a radiation source (e.g., a laser or electrically resistiveheater) for heating the disk surface 122. As the magnetic disk 112rotates, the slider 113 moves radially in and out over the disk surface122 so that the magnetic head assembly 121 may access different tracksof the magnetic disk 112 where desired data are written. Each slider 113is attached to an actuator arm 119 by way of a suspension 115. Thesuspension 115 provides a slight spring force which biases slider 113towards the disk surface 122. Each actuator arm 119 is attached to anactuator means 127. The actuator means 127 as shown in FIG. 1A may be avoice coil motor (VCM). The VCM includes a coil movable within a fixedmagnetic field, the direction and speed of the coil movements beingcontrolled by the motor current signals supplied by control unit 129.

During operation of a HAMR enabled disk drive 100, the rotation of themagnetic disk 112 generates an air bearing between the slider 113 andthe disk surface 122 which exerts an upward force or lift on the slider113. The air bearing thus counter-balances the slight spring force ofsuspension 115 and supports slider 113 slightly above the disk 112surface by a small, substantially constant spacing during normaloperation. The radiation source heats up the high-coercivity data bitsso that the write elements of the magnetic head assemblies 121 maycorrectly magnetize the data bits.

The various components of the disk storage system are controlled inoperation by control signals generated by control unit 129, such asaccess control signals and internal clock signals. Typically, thecontrol unit 129 includes logic control circuits, storage means and amicroprocessor. The control unit 129 generates control signals tocontrol various system operations such as drive motor control signals online 123 and head position and seek control signals on line 128. Thecontrol signals on line 128 provide the desired current profiles tooptimally move and position slider 113 to the desired data track on disk112. Write and read signals are communicated to and from write and readheads on the assembly 121 by way of recording channel 125.

The above description of a typical magnetic disk storage system and theaccompanying illustration of FIG. 1A are for representation purposesonly. It should be apparent that disk storage systems may contain alarge number of disks and actuators, and each actuator may support anumber of sliders.

FIG. 1B is a cross sectional schematic of a HAMR enabled write head 101,according to one embodiment of the invention. The head 101 includes aphotonic integrated circuit 135. The photonic integrated circuit 135includes a plurality of optical elements such as an optical detector130, an optical emitter 132 and an optical element 134 that is distinctfrom the optical detector 130 and the optical emitter 132. The opticaldetector 130 may be a photodiode for optical power monitoring, such as aPN photodiode, a PIN photodiode, an avalanche photodiode, aphototransistor, a metal-semiconductor-metal photodiode, or aphotoresistor. The optical emitter 132 may be any suitable opticalemitter such as a light-emitting diode (LED), a superluminescent LED, aFabry Perot laser diode, a distributed Bragg reflector laser diode, adistributed feedback laser diode, a resonant cavity LED, a microdisklaser, a quantum cascade laser or a vertical-cavity surface-emittinglaser. The optical element 134 may be a solid immersion lens, a solidimmersion mirror, an optical modulator, a distributed Bragg reflector, amicrodisk resonator, a feedback waveguide coupler, an optical filter, aspot size convertor or a diffraction grating.

The optical emitter 132, such as a laser, delivers radiation to a nearfield transducer (NFT) 140—e.g., a plasmonic device or an opticaltransducer—which is located at or near the air-bearing surface (ABS).The optical element 134, such as a solid immersion lens, enables morelight to be focused on the NFT 140. The utilization of the solidimmersion lens also provides a wider optical emitter 132, which willenable more power to be delivered at a lower current density. Theoptical detector 130 enables the laser power to be monitored directlyduring magnetic recording. The NFT 140 further focuses the beamspot toavoid heating neighboring tracks of data on the disk 112—i.e., creates abeamspot much smaller than the diffraction limit. As shown by arrows142, this optical energy emits from the NFT 140 to the surface of thedisk 112 below the ABS of the head 101. The embodiments herein are notlimited to any particular type of NFT and may operate with, for example,either a c-aperature, e-antenna plasmonic near-field source, or anyother shaped transducer known in the art.

FIG. 2 illustrates a cross-sectional schematic diagram of a HAMR enableddisk drive, according to one embodiment of the invention. Specifically,FIG. 2 illustrates a portion of a head 201 and associated perpendicularmagnetic recording disk 112 for a HAMR disk drive which uses thephotonic integrated circuit 135 for generating and directing heat to thedisk 112. The disk 112 includes a substrate and a perpendicular magneticrecording layer (RL) 246. In one embodiment, the disk 112 may include anoptional “soft” or relatively low-coercivity magnetically permeableunderlayer (SUL). However, the SUL is not required for a HAMR disk drive100.

The RL 246 may be any media with perpendicular magnetic anisotropy, suchas a cobalt-chromium (CoCr) alloy granular layer grown on a specialgrowth-enhancing sublayer, or a multilayer of alternating films of Cowith films of platinum (Pt) or palladium (Pd). The RL 246 may also be anL1₀ ordered alloy such as FePt or FeNiPt. The disk 112 may also includea protective overcoat (not shown) over the RL 246.

The head 201 has a substrate trailing surface 211 and an ABS surfaceoriented generally perpendicular to trailing surface 211. The trailingsurface 211 is typically formed of a composite material, such as acomposite of alumina/titanium-carbide (Al₂O₃/TiC), and supports the readand write elements which are typically formed as a series of thin filmsand structures on the trailing surface 211. The disk 112 may spin in adirection 223 away from the trailing surface 211 and towards the otherlayers of the head 201. The ABS is the recording-layer-facing surface ofthe slider that faces the disk 112. Note that FIG. 2 is not drawn toscale because of the difficulty in showing the very small features and,for the sake of clarity, omits structures from the head such as spacingand insulating layers.

The head 201 includes a magnetoresistive read pole 215 located betweenshields S1 and S2, and a perpendicular write head that includes amagnetic yoke 220 with a write pole 220 a, a return pole 220 b, and anelectrically conductive coil 225. The write pole 220 a is formed of ahigh-moment material, such as a NiFe or FeCoNi alloy. The write coil 225is wrapped around the yoke 220 with the electrical current directionsbeing shown as into the paper by the coil cross-sections marked with an“X” and out of the paper by the coil cross-sections marked with a solidcircle. When write-current pulses are directed through the coil 225, thewrite pole 220 a directs magnetic flux, represented by arrow 230, to theRL 246. Further, the magnetic flux 230 continues through the substrateor a SUL layer before arriving at the return pole 220 b. However, theinvention is not limited to the structure and material discussed above.For example, the coil 225 may be a helical coil or the write pole 220 amay include a wrap-around shield. Further, the present invention mayoperate with any recording head that can perform the functions discussedherein.

The head 201 may also include a non-magnetic material 251 between thereturn pole 220 b and the write pole 220 a. The non-magnetic material251 may include SiO₂ and Al₂O₃. The photonic integrated circuit 135having an optical detector 130, an optical emitter 132, and an opticalelement 134 distinct from the optical detector 130 and the opticalemitter 132, as well as the NFT 140 are embedded in the non-magneticmaterial 251. The photonic integrated circuit 135 may extend through theyoke 220 and is located between the write pole 220 a and the return pole220 b. As noted by the ghosted lines, the yoke 220 may continuouslyconnect the write pole 220 a to the return pole 220 b. The photonicintegrated circuit 135 and the NFT 140 may be fabricated at any locationsuch that the NFT 140 passes over a portion of the spinning magneticdisk 112 prior to that portion passing below the write pole 220 a.Specifically, the photonic integrated circuit 135 may be located betweenshield S2 and return pole 220 b, or between the write pole 220 a and theouter face 231 of the head 201 (if the disk 112 rotates opposite of thedirection 223 shown).

While writing to the disk 112, the RL 246 moves relative to the head 201in the direction shown by arrow 223. In HAMR, the optical energy 142emitted from the NFT 140 temporarily lowers the coercivity (H_(c)) ofthe RL 246 so that the magnetic recording regions 227, 228, 229 may beoriented by the write field from write pole 220 a. The magneticrecording regions 227, 228, 229 become oriented by the write field ifthe write field (H_(w)) is greater than H_(c). After a region of the RL246 in the data track has been exposed to H_(w) from the write pole 220a and the resulting heat from the optical energy 142 from the NFT 140,the region's temperature falls below the Curie temperature and the dataassociated with the magnetic orientations is recorded. Specifically, thetransitions between recorded regions (such as previously recordedregions 227, 228, and 229) represent written data “bits” that can beread by the read pole 215. In this manner, the NFT 140 uses the opticalenergy 142 to heat the RL layer 246 and lower its magnetic coercivity.

The photonic integrated circuit 135 is formed during the processing ofthe head 201, which eliminates the need for optical coupling theoptoelectronic elements to various waveguides that then guide the lightonto the NFT 140 to generate the heat spot. The elements of the photonicintegrated circuit 135 may be all fabricated from the same semiconductorthin films that are transferred to the head 201. Thus, the challengingmechanical alignment operations to achieve the efficient coupling to thewaveguide are avoided. FIGS. 3A-3F describe a process of forming thephotonic integrated circuit 135 in the head 201 according to oneembodiment of the invention.

FIG. 3A is a cross-sectional view of a substrate 302 and a partiallyfabricated recording head 304. The substrate 302 may be a compositematerial, such as a composite of alumina/titanium-carbide (AlTiC), andmay have the trailing surface 211 on which the read and write elementsare formed by a series of deposition processes of thin films andstructures. The partially fabricated recording head 304 may includeparts of the head 201, such as the shields S1 and S2, the read pole 215,and the return pole 220 b, that are trailing to the photonic integratedcircuit 135 as shown in FIG. 2. Alternatively, the partially fabricatedrecording head 304 may include parts that are leading to the photonicintegrated circuit 135, such as the coils 225 and the write pole 220 a,as shown in FIG. 2.

FIG. 3B is a top view of the partially fabricated recording head 304.The surface 305 may have been planarized by one or more chemicalmechanical polishing (CMP) processes and may include a non-magneticmaterial 306, a first metal contact 308 for the optical detector 130, asecond metal contact 310 for the optical emitter 132, and magnetic backgaps 312. FIG. 3C is a cross-sectional view of a second substrate 320, asacrificial layer 322, and one or more additional layers 324. The secondsubstrate 320 may comprise gallium arsenide (GaAS), the sacrificiallayer 322 may comprise an aluminum arsenide (AlAs) layer, a straininduced fracture layer, or a germanium (Ge) layer, and the one or moreadditional layers 324 may comprise of one or more III-V semiconductormaterials. An example of a strain induced fracture layer that is usedfor the sacrificial layer 322 is a pseudomorphically grown III-V latticemismatched layer such as indium gallium arsenide (InGaAs). Anotherexample of a strain induced fracture layer is a damaged layer created byproton bombardment.

In one embodiment, as shown in FIG. 3C, the one or more additionallayers 324 include a first layer 326 disposed on the sacrificial layer322 and a second layer 328 disposed on the first layer 326. The firstlayer 326 may be an n-type III-V semiconductor layer, such as n-typealuminum gallium arsenide (AlGaAs), or a p-type III-V semiconductorlayer, such as p-type AlGaAs. The second layer 328 may be a p-type III-Vsemiconductor layer, such as p-type AlGaAs, or an n-type III-Vsemiconductor layer, such as n-type AlGaAs. The layers 326, 328 may beformed epitaxially. The one or more additional layers 324 are notlimited to the first and second layers 326, 328. From the one or moreadditional layers 324, the photonic integrated circuit 135 may be formedusing various photolithographic processes. Any layer structure suitablefor forming the photonic integrated circuit 135 may be utilized as theone or more additional layers 324. In one embodiment, the one or moreadditional layers 324 may include structures such as heterojunction, aquantum well, and/or metallic ohmic contacts. The quantum well maycomprise a GaAs layer sandwiched between two AlGaAs layers.

As shown in FIG. 3D, the substrate 320 with the layers 324 and 322disposed thereon is bonded with the substrate 302 having the partiallyfabricated recording head 304 disposed thereon. Particularly, the secondlayer 328, such as a p-type AlGaAs layer, is bonded to the surface 305of the partially fabricated recording head 304. The bonding may beachieved by any suitable bonding method. In one embodiment, the bondingis achieved by the second layer 328 forming Van der Waals bond to thesurface 305. In another embodiment, an epoxy layer is used to bond thesecond layer 328 to the surface 305.

Next, the sacrificial layer 322 and the second substrate 320 are removedfrom the structure, as shown in FIG. 3E. In one embodiment, the removalis achieved by an epitaxial lift-off. The epitaxial lift-off may beperformed by etching away the sacrificial layer 322 with a highlyselective etch process. For an AlAs sacrificial layer 322, aqueoushydrofluoric acid (HF) is used to etch the AlAs sacrificial layer 322.As the AlAs sacrificial layer 322 is etched away, the second substrate320 is removed from the stack. For a Ge sacrificial layer 322, xenondifluoride (XeF₂) dry etch is used. The epitaxial lift-off may be alsoperformed by removing the sacrificial layer 322 through various thermaland mechanical treatments, such as rapid temperature quench ormechanical force, when the sacrificial layer 322 is a strain inducedfracture layer.

As shown in FIG. 3F, one or more photolithographic processes areperformed on the one or more additional layers 324 to form the photonicintegrated circuit 135. The photonic integrated circuit 135 includes theoptical detector 130, the optical emitter 132, and the optical element134 from the one or more additional layers 324. The optical detector 130may be formed on the first metal contact 308 and the optical emitter maybe formed on the second metal contact 310. In addition, the NFT 140 maybe formed on the partially fabricated recording head 304. Byincorporating the photonic integrated circuit 135 directly into thesubstrate process, the NFT 140 is self aligned with the elements of thephotonic integrated circuit 135. In one embodiment, the NFT 140 isformed on the partially fabricated recording head 304 before thetransferring of the one or more additional layers 324 to the partiallyfabricated recording head 304. After the formation of the photonicintegrated circuit 135 and the NFT 140, subsequent processing isperformed to build the remainder of the electrical and magnetic elementsnecessary to complete the recording head.

The process illustrated in FIGS. 3A-3F shows transferring of full layers324 from the second substrate 320 to the partially fabricated recordinghead 304. In other embodiments, the layers 324 are first processed usingmicro-fabrication to isolate semiconductor mesas before transferring tothe partially fabricated recording head 304. Before the transferring ofthe semiconductor mesas to the partially fabricated recording head 304,metal contacts may be formed on the semiconductor mesas. After thetransferring to the partially fabricated recording head 304, thesemiconductor mesas are processed to form the photonic integratedcircuit 135 by one or more photolithographic processes.

As illustrated in FIGS. 3A-3F, the one or more additional layers 324 aretransferred from the second substrate 320 directly to the partiallyfabricated recording head 304. In one embodiment, the one or moreadditional layers 324 are first transferred to a carrier substrate andthen transferred to the partially fabricated recording head 304 from thecarrier substrate. FIGS. 4A-4G illustrate such process.

The process starts with the first substrate 302 and the partiallyfabricated recording head 304 disposed on the first substrate 302, asshown in FIG. 4A. FIG. 4B is a cross-sectional view of a secondsubstrate 402, a sacrificial layer 404, and one or more additionallayers 406. The second substrate 402 may comprise GaAS, the sacrificiallayer 404 may comprise an AlAs layer, a strain induced fracture layer,or a Ge layer, and the one or more additional layers 406 may comprise ofone or more III-V semiconductor materials. An example of a straininduced fracture layer that is used for the sacrificial layer 404 is apseudomorphically grown III-V lattice mismatched layer such as InGaAs.Another example of a strain induced fracture layer is a damaged layercreated by proton bombardment.

In one embodiment, as shown in FIG. 4B, the one or more additionallayers 406 include a first layer 408 disposed on the sacrificial layer404 and a second layer 410 disposed on the first layer 408. The firstlayer 408 may be a p-type III-V semiconductor layer, such as p-typeAlGaAs, or a n-type III-V semiconductor layer, such as n-type AlGaAs.The second layer 410 may be an n-type III-V semiconductor layer, such asn-type AlGaAs, or a p-type III-V semiconductor layer, such as p-typeAlGaAs. The layers 408, 410 may be formed epitaxially. The one or moreadditional layers 406 are not limited to the first and second layers408, 410. From the one or more additional layers 406, the photonicintegrated circuit 135 may be formed using various photolithographicprocesses. Any layer structure suitable for forming the photonicintegrated circuit 135 may be utilized as the one or more additionallayers 406. In one embodiment, the one or more additional layers 406 mayinclude structures such as a heterojunction, a quantum well, and/ormetallic ohmic contacts. The quantum well may comprise a GaAs layersandwiched between two AlGaAs layers.

Next, a third substrate 420 is formed over the one or more additionallayers 406, as shown in FIG. 4C. The third substrate 420 may be acarrier substrate that is made of a rigid material such as metal, glass,or silicon. Alternatively, the carrier substrate may be made of aflexible material such as flexible metal or polymer such as polyamide.An epitaxial lift-off may be performed to remove the sacrificial layer404 and the second substrate 402, as shown in FIG. 4D. Again theepitaxial lift-off may be performed by etching away the sacrificiallayer 404 with a highly selective etch process. For an AlAs sacrificiallayer 404, aqueous HF is used to etch the AlAs sacrificial layer 404. Asthe AlAs sacrificial layer 404 is etched away, the second substrate 402is removed from the stack. For a Ge sacrificial layer 404, XeF₂ dry etchis used. The epitaxial lift-off may be also performed by removing thesacrificial layer 404 through various thermal and mechanical treatments,such as rapid temperature quench or mechanical force, when thesacrificial layer 404 is a strain induced fracture layer. At the end ofthe epitaxial lift-off, the first layer 408 is exposed.

Next, the first layer 408 is bonded to the partially fabricatedrecording head 304, as shown in FIG. 4E. The bonding may be achieved byany suitable bonding method. In one embodiment, the bonding is achievedby the first layer 408 forming Van der Waals bond to the partiallyfabricated recording head 304. In another embodiment, an epoxy layer isused to bond the first layer 408 to partially fabricated recording head304.

The third substrate 420 is then removed using any suitable removalmethod, such as etching or CMP, leaving the one or more additionallayers 406 exposed as shown in FIG. 4F. Next, one or morephotolithographic processes are performed to form the photonicintegrated circuit 135 from the one or more additional layers 406. Thephotonic integrated circuit 135 includes the optical detector 130, theoptical emitter 132, and the optical element 134 from the one or moreadditional layers 406. In addition, the NFT 140 may be formed on thepartially fabricated recording head 304. By incorporating the photonicintegrated circuit 135 directly into the substrate process, the NFT 140is self aligned with the elements of the photonic integrated circuit135. In one embodiment, the NFT 140 is formed on the partiallyfabricated recording head 304 before the transferring of the one or moreadditional layers 406 to the partially fabricated recording head 304.After the formation of the photonic integrated circuit 135 and the NFT140, subsequent processing is performed to build the remainder of theelectrical and magnetic elements necessary to complete the recordinghead.

The process illustrated in FIGS. 4A-4G shows transferring of full layers406 from the second substrate 402 to the partially fabricated recordinghead 304. In other embodiments, the layers 406 are processed usingmicro-fabrication to isolate semiconductor mesas before transferring tothe partially fabricated recording head 304. Before the transferring ofthe semiconductor mesas to the partially fabricated recording head 304,metal contacts such as metallic ohmic contacts may be formed on thesemiconductor mesas. After the transferring to the partially fabricatedrecording head 304, the semiconductor mesas are processed to form thephotonic integrated circuit 135 by one or more photolithographicprocesses.

In summary, a method for forming a HAMR device is disclosed. One or morelayers are formed on a substrate and subsequently transferred to apartially fabricated recording head. The one or more layers may beprocessed to form semiconductor mesas before the transfer. Aftertransferring the one or more layers or the semiconductor mesas to thepartially fabricated recording head, one or more photolithographicprocesses are performed on the one or more layers or the semiconductormesas to form a photonic integrated circuit having an optical detector,an optical emitter and an optical element distinct from the opticaldetector and the optical emitter. An NFT may be formed on the partiallyfabricated recording head before or after the transferring of the one ormore layers or the semiconductor mesas. By incorporating the photonicintegrated circuit 135 directly into the substrate process, the NFT 140is self aligned with the elements of the photonic integrated circuit135.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A heat assisted magnetic recording device,comprising: an optical detector; an optical emitter; an optical elementdistinct from the optical detector and the optical emitter, wherein theoptical detector, the optical emitter, and the optical element arealigned in order; and a near field transducer, wherein the opticaldetector, the optical emitter and the optical element are aligned withthe near field transducer.
 2. The heat assisted magnetic recordingdevice of claim 1, wherein the optical element comprises a solidimmersion lens, a solid immersion mirror, an optical modulator, adistributed Bragg reflector, a microdisk resonator, a feedback waveguidecoupler, an optical filter, a spot size convertor or a diffractiongrating.
 3. The heat assisted magnetic recording device of claim 1,wherein the optical emitter comprises a LED, a superluminescent LED, aFabry Perot laser diode, a distributed Bragg reflector laser diode, adistributed feedback laser diode, a resonant cavity LED, a microdisklaser, a quantum cascade laser or a vertical-cavity surface-emittinglaser.
 4. The heat assisted magnetic recording device of claim 1,wherein the optical detector comprises a PN photodiode, a PINphotodiode, an avalanche photodiode, a phototransistor, ametal-semiconductor-metal photodiode, or a photoresistor.
 5. A heatassisted magnetic recording device, comprising: an actuator; a magneticdisk; one or more magnetic head assemblies, wherein at least onemagnetic head assembly comprises: an optical detector; an opticalemitter; an optical element distinct from the optical detector and theoptical emitter, wherein the optical detector, the optical emitter, andthe optical element are aligned in order; and a near field transducer,wherein the optical detector, the optical emitter and the opticalelement are aligned with the near field transducer.
 6. The heat assistedmagnetic recording device of claim 5, wherein the optical elementcomprises a solid immersion lens, a solid immersion mirror, an opticalmodulator, a distributed Bragg reflector, a microdisk resonator, afeedback waveguide coupler, an optical filter, a spot size convertor ora diffraction grating.
 7. The heat assisted magnetic recording device ofclaim 5, wherein the optical emitter comprises a LED, a superluminescentLED, a Fabry Perot laser diode, a distributed Bragg reflector laserdiode, a distributed feedback laser diode, a resonant cavity LED, amicrodisk laser, a quantum cascade laser or a vertical-cavitysurface-emitting laser.
 8. The heat assisted magnetic recording deviceof claim 5, wherein the optical detector comprises a PN photodiode, aPIN photodiode, an avalanche photodiode, a phototransistor, ametal-semiconductor-metal photodiode, or a photoresistor.